Pact Adept (5e Feat)
From D&D Wiki
Prerequisites: Charisma 18, two ranks in Pact Initiate, level 10.
Your patron has noticed your efforts in furthering their goals and has decided to give you the following.
Increase your Charisma by 1, to a maximum of 20
gain one warlock spell slot of 4th level
gain the 10th level feature of your patron
You learn one eldritch invocation of 7th level